There is a major effort in the communication industry to add broadband video services to the telephone network. For technical and economic reasons, the transmitted video will most likely be in digital form, requiring a data rate of over 100 Mb/s. Since this high information rate is a thousand-fold greater than that of digitized voice, it will require techniques that emphasize high-speed performance.
Although optical switching has great switching potential, it is not yet ready for deployment. Consequently, electronic switching will be utilized in the first introduction of broadband video. The industry is focusing on CMOS space switching as the most straightforward broadband switching technique due to its high speed, high density, and low power dissipation. However, conventional broadband space switches reported have been limited to predominantly 16.times.16 arrays. As the size of the arrays is increased, the switching speed decreases due to a geometric increase in crosspoints and associated parasitic elements.
The aforementioned copending application discloses a broadband switch array as shown in FIG. 1 that attempts to reduce the aforementioned problem of stray capacitances by connecting the rows to each column with a tree structure as opposed to a direct connection. The matrix in FIG. 1 is basically a parallel combination of multiplexers each connected to the same input lines. The multiplexing operation is accomplished with a plurality of cascaded stages arranged into a tree configuration 78 wherein each stage is comprised of 2:1 selector elements 73.